The Cassini mission to Saturn was to be the last of NASA's
"flagship" missions: large, expensive and technologically
advanced. Its origins were in a 1982 study of possible joint
NASA/European Space Agency missions. This had suggested a Saturn
orbiter with an atmospheric entry probe intended for the large moon
Titan would be a high priority project. But due to both the
fiscal climate of the early 1980s and to difficulties in
negotiations, the mission was not approved until 1989.

Flagship projects at JPL had the benefit of funding development of new spacecraft
technologies that smaller, less expensive missions could not
afford. Cassini-funded technologies were adopted by Mars Global
Surveyor, Mars Pathfinder and the Spitzer Space Telescope among many
others. When Cassini came under attack in 1993 and 1994 for its $3.3
billion price tag, defending it meant protecting these other efforts,
too.

Somewhat later in its development, Cassini faced a legal challenge filed by activists opposed to its use of radioisotope
thermoelectric generators and mission trajectory involving an Earth swingby. A legal challenge to the mission's
Environmental Impact Statement was filed in federal court in Hawaii right before launch in an attempt to stop the mission. It was rejected by both the federal district court in Hawaii and the Ninth Circuit Court of Appeals, clearing the mission's path.

A Titan IV rocket hurled Cassini-Huygens on its way to Saturn on Oct.
15, 1997. On Jul., 1 2004, after flybys of Venus, Earth and Jupiter,
the spacecraft reached Saturn and attained orbit. This mission is
still active.